Figure 1

Assessment of cell death and apoptosis induced by TK VI. (A) Cells were treated with TK VI or etoposide, ranging from 10 to 40 μM and incubated in 10% FBS-DMEM complete medium at 37°C for 24 h. Viable cells were measured by MTT assay. Results were expressed as means ± SD of triplicate experiments (each performed in duplicate). Black solid line: HepG2 cells; Red short dash line: BGC cells; Blue dot line: A549 cells. Asterisks indicated values significantly different from cells treated with etoposide. *P < 0.05; **P < 0.01. (B) Cells were treated with 20 μM TK VI for 8 h and then apoptosis were analyzed on a flow cytometer using annexin V/PI staining methods. Data were representative of three independent experiments. Numbers in the respective quadrants indicated the percentage of the cells present in this area. (C) The HepG2, Hep3B and Chang liver cells were incubated with TK VI and detected as described in A. Results were expressed as means ± SD of triplicate experiments (each performed in duplicate). ## indicated values significantly different from Chang liver cells (^##P < 0.05). (D) HepG2 cells were treated with 20 μM TK VI or etoposide for 24 h. Then DNA fragmentation in the cells was viewed using fluorescence microscopy. (E) The quantitative analysis of apoptosis in cells was analyzed by FACS using TUNEL staining. Results were expressed as means ± SD of triplicate experiments (each performed in duplicate). Asterisks indicated values significantly different from controls and Z-VAD-treated cells. **P < 0.01. (F) DNA was extracted from HepG2 cells cultured for 36 h with 20 μM TK VI and DNA ladder was detected by agarose gel electrophoresis.